5 Symptoms of Low Potassium

You probably know bananas are loaded with potassium, but you may not realize the vital role this mineral plays in the body. Potassium aids in muscle contraction, fluid regulation, and mineral balance. What's more, potassium blunts the effects of excessive sodium consumption—a problem most Americans have.

The average U.S. adult in 2022 took in 3,400 milligrams of salt per day, nearly 50% more than the recommended upper limit of 2,300 milligrams, according to the US Food & Drug Administration (FDA). A potassium-rich diet helps the body flush out sodium.

It also helps relax blood vessel walls and, in turn, lower blood pressure. Increasing your potassium intake while reducing your sodium intake can lower your chances of heart disease, according to a 2018 review published in the journal Clinical Nutrition.

If you eat lots of foods that come in a bag or box, then you're almost surely low on potassium, said Lauren Blake, RD, a dietitian who worked at The Ohio State University Wexner Medical Center. Upping your intake of whole fruits and vegetables will help you hit the expert-recommended 4,700 milligrams of potassium a day. Other foods such as yogurt and clams are rich in potassium. You should also check in with your healthcare provider if you suspect you need more potassium.

Some people don't even feel small reductions in blood potassium levels. However, there are symptoms to watch out for before the reduction becomes severe, according to the National Library of Medicine MedlinePlus resource. Here are the biggest signs you're running low on potassium—a condition called hypokalemia.

You're Always Tired

If you can't seem to rest enough and your energy levels are low, you may be potassium deficient, Blake said. "Every cell in your body needs the right amount of potassium to function," Blake explained. "If you are increasingly exhausted and know you are getting enough sleep, potassium might be the cause."

That said, other issues with your diet, stress, or sleep deprivation can also leave you feeling chronically sluggish, so you shouldn't assume a potassium deficiency is a culprit. Watch for additional symptoms.

You Have Muscle Weakness or Cramping

Potassium plays a key role in smooth muscle contraction, both in the heart and across the entire body. So when potassium levels are low, you might experience "aches and spasms" throughout the day or while exercising, Blake said. You may even experience muscle damage, according to MedlinePlus.

You Feel Faint, Dizzy, or Tingly

Potassium can wax and wane throughout the day, and a large drop can slow your heartbeat, making you feel like you're going to pass out. "This is not common, and many other factors can be the cause, but it's important to see your doctor if you experience this," Blake said.

Tingling arms or legs is another signal you shouldn't ignore. You may experience numbness as well.

You Have High Blood Pressure or Heart Palpitations

Without enough potassium, blood vessel walls can become constricted, which results in hypertension, or high blood pressure, Blake said. This condition has no symptoms, but can lead to serious health problems, according to MedlinePlus. If you're worried, make sure you check your blood pressure regularly at home or at your healthcare provider's office.

Also, watch out for heart palpitations; the heart muscle has more difficulty pumping when the sodium-potassium balance is out of whack. When you get palpitations, you may feel very aware of your heartbeat or feel like your heart skipped or stopped some beats, according to Medline Plus.

You're Bloated or Constipated All the Time

Constipation is the first symptom of hypokalemia listed on MedlinePlus, so it's something to watch for. Additionally, when you're low on potassium, your body struggles to regulate its sodium levels, which can cause salt-induced bloating.